Many Help XHP files ends with "Related topics" at the bottom. The "Related Topics" was implemented with <embed href="text/shared/00/00000004.xhp#related"/> (...) But it also can be implemented with <section id="relatedtopics"> (...) </section> The task is to replace the <embed ...> with the <section id=...>.
Olivier Hallot committed a patch related to this issue. It has been pushed to "master": https://git.libreoffice.org/help/commit/ed90b5c51e0cda59e30995bbfb26d9ea69123fe8 tdf#154364 (part) refactor "related topics" for swriter/guide/
Olivier Hallot committed a patch related to this issue. It has been pushed to "master": https://git.libreoffice.org/help/commit/7062dbc3016bf22b8294a7d6998e0441523f1895 tdf#154364 (part) refactor "related topics" for swriter
+1 from my side!
Olivier Hallot committed a patch related to this issue. It has been pushed to "master": https://git.libreoffice.org/help/commit/7484a8aa5d9f1350d4272aa3a1ed894cc05e102e tdf#154364 (part) refactor "related topics" for smath
Olivier Hallot committed a patch related to this issue. It has been pushed to "master": https://git.libreoffice.org/help/commit/802dff23502b199e496847b3091a557e8e4c793b tdf#154364 (part) refactor "related topics" for simpress
Olivier Hallot committed a patch related to this issue. It has been pushed to "master": https://git.libreoffice.org/help/commit/68257fa557206cc11dfcad9fdb037eaceb131217 tdf#154364 (final) refactor "related topics" for share/guide